Replacing a Camera with a Computer: Computational Imaging with Professor Laura Walker

How can we capture the world based on how light interacts? On November 1st, Professor Laura Walker spoke at Femtech Talk about how computational imaging does this. Computational imaging is a multidisciplinary field that blurs the lines of electrical engineering, computer science, and biology. It focuses on the physics of how light propagates, and the algorithms that can be developed for optimization.

The Computer as a Lens

But what exactly is computational imaging? What kind of problems can be solved in the field? Walker describes computational imaging as hardware and software working together. Optics, Walker says, is trying to design lenses in a camera so that they take better pictures. But computational imaging is “rethinking how we make this camera in the first place”! Traditional imaging systems are boring. “Can computers do the job of lenses?”, she proposes to her audience.

More specifically, computational imaging focuses on how to design the image system, given sensors and an object. The design process is like art, Walker explains. The design must be practical, cheap, and efficient, so computational imagers must consider how to redesign hardware for easy computation. They also must be familiar both with optics and signal processing to accomplish this.

Applying Computational Imaging to the Real World

The applications of computational imaging are numerous and varied. Walker introduces the Light Field camera, one such application. This camera collects data in a different way than a normal camera, so that you can change the focus of a picture from the background to the foreground after you’ve taken it! Walker explains that the rays hitting the sensor can be computationally back traced to accomplish the digital refocusing.

Another application is Computational phase imaging, an application of computational imaging that essentially gets a map of surface shape and the density of cells. It helps scientists see which cells are transparent, and is therefore useful for disease diagnosis. In malaria, for example, it allows us to look for an infected cell among tens of thousands of red blood cells!

Getting into Research as an Undergrad

And how might someone get involved in computational imaging? Walker mentions she got involved in optics quite randomly; she emailed a bunch of CS professors and happened to get a position in optics! She also says that she did a lot of work in signal processing as an undergrad. Most importantly, the Berkeley Center of Computational Imaging is expanding! She greatly encourages undergrads to get involved in research; in computational imaging, there are both building and coding projects for undergrads to work on.

Walker also emphasizes the importance of having diversity in technology, and of always checking your biases. She encourages her audience: “Be bold. Be resilient. This is wonderful place to work in, sometimes not the best culture and environment, but you can get around that and be happy.”